SF patch #1438387, PEP 328: relative and absolute imports.

 - IMPORT_NAME takes an extra argument from the stack: the relativeness of
   the import. Only passed to __import__ when it's not -1.

 - __import__() takes an optional 5th argument for the same thing; it
   __defaults to -1 (old semantics: try relative, then absolute)

 - 'from . import name' imports name (be it module or regular attribute)
   from the current module's *package*. Likewise, 'from .module import name'
   will import name from a sibling to the current module.

 - Importing from outside a package is not allowed; 'from . import sys' in a
   toplevel module will not work, nor will 'from .. import sys' in a
   (single-level) package.

 - 'from __future__ import absolute_import' will turn on the new semantics
   for import and from-import: imports will be absolute, except for
   from-import with dots.

Includes tests for regular imports and importhooks, parser changes and a
NEWS item, but no compiler-package changes or documentation changes.
diff --git a/Python/bltinmodule.c b/Python/bltinmodule.c
index 24c99f4..409afd8 100644
--- a/Python/bltinmodule.c
+++ b/Python/bltinmodule.c
@@ -37,11 +37,13 @@
 	PyObject *globals = NULL;
 	PyObject *locals = NULL;
 	PyObject *fromlist = NULL;
+	int level = -1;
 
-	if (!PyArg_ParseTuple(args, "s|OOO:__import__",
-			&name, &globals, &locals, &fromlist))
+	if (!PyArg_ParseTuple(args, "s|OOOi:__import__",
+			&name, &globals, &locals, &fromlist, &level))
 		return NULL;
-	return PyImport_ImportModuleEx(name, globals, locals, fromlist);
+	return PyImport_ImportModuleLevel(name, globals, locals,
+					  fromlist, level);
 }
 
 PyDoc_STRVAR(import_doc,